Why i lack empathy for people?

i have seen so many bad thing happen on the news it like its nothing special to me anymore. for example some guy killed 9 of his children and i did not get mad or nothing. to me it to me it was bad but i the way i looked at it was like i seen this plenty of times before so their was no need to a big reaction. I look at things like that as an everyday occurrence so i do not really get mad all i feel is sympathy for them . The only time i feel really bad for people is if i can relate to them.also i have sympathy for people starving around the world and other stuff like that.